Spray dried products



United States Patent 3,380,922 SPRAY DRIED PRODUCTS Gordon G. Shields, Downey, and Charles B. Patterson, Lakewood, Calif., assignors to Purex Corporation, Ltd., Lakewood, Calif., a corporation of California No Drawing. Filed Sept. 23, 1965, Ser. No. 489,761 Claims. (Cl. 252-99) ABSTRACT OF THE DISCLOSURE Film forming synthetic resinous polymers having the repeating unit oooht oootn E ii Ln H H J have been found to be efiective binders for headed inorganic salt base products such as synthetic detergents.

This invention relates to water soluble or water dispersible spray-dried products having improved mechanical stability. More particularly, the invention is directed to inorganic salt base products in the form of spraydried beads possessing improved resistance to attrition resulting from their being handled by various mechanical devices such as belt conveyors, bucket elevators, discharge into and passage through hoppers and bins, and due to vibration during shipment via railroads and motor trucks.

The invention aims to improve any of a variety of spray dried compositions usable alone or admixed with other materials, depending upon the nature and intended purpose of the final product. Primarily the invention is concerned with what may be termed salt-base-containing compositions usable in a variety of household and industrial products, and which include one or more inorganic water soluble salts, of which so-called builder salts such as the alkali metal phosphates (e.g. tr-isodium, tetrasodium phosphates and sodium tripolyphosphate), sulfates, carbonates and silicates, are illustrative. For various reasons it is advantageous to produce such salt bases in the form or spray dried particles in hollow bead form, and in which the alkaline salt or salt mixture is the major constituent of the beads. Thus, the beads may range in composition from virtually 100% salts, to compositions that may contain relatively small quantities of other materials such as surfactants, dyes, oils and perfumes, depending upon the end product desired.

In terms of end product, the invention contemplates improved bleaching and disinfecting products in which a spray dried base is mixed with solid organic chlorinated material whose available chlorine content is such as to render the product effectively usable for household and industrial bleaches. Accordingly, in the broader contemplations of this aspect of the invention, we may use any of various known types of solid chlorinated organic materials having desirable content of available chlorine.

With respect to dry bleach compositions, the spray dried base may contain a relatively small amount of a suitable surfactant, preferably anionic, to give the product detersive and foaming properties. It is "to be understood that we may use any of the many known soaps or synthetic surfactants as the detersive component of the base, and that the prior art and commercial practice pertaining to household and commerical detergents is replete with known surfactants that are used in solid or spray dried detersive products. In a spray dried base to be formulated with a solid organic chlorinated "ice material, we prefer to use a suitable anionic surfactant such as the Oronite type of alky a-ryl sulfonates, e.g. alkyl metal dodecyl benzene sulfonate, although at greater expense, other surfactants such as the fatty acid sul fate-s, e.g. alkali metal lauryl sulfate, may be used.

Various advantages of the invention are applicable to detergent compositions totally oontainablc in the spray dried beads, particularly with respect to lower active level detergents where the surfactant content may not exceed about 20% by weight of the bead composition. The relatively high preponderance of the builder salt content, e.g. in excess of and commonly greater than normally would render the beads subject to undesirably high attrition losses which are desirably minimized in accordance with the invention. Thus where the spray-dried material is a total detergent formulation, the beads will contain not more than about 20% non-ionic, cationic or anionic organic surfactant, the balance consisting of alkaline builder salt together with minor percentages of such additives as dyes, brighteners, oils and the like, all in uniform admixture resulting from the spray drying of an aqueous solution or slurry of the components.

The mechanical aspects of conventional spray drying are well known. Generally the procedure involves forming an aqueous slurry of product components, spray drying the slurry to solid hollow bead form, and collecting and transferring the beads to a packaging station by systems that may vary in detail but which conventionally will involve the use of traveling conveyors, elevators and possibly mixers, all of which subject the beads to vibration or agitation, and therefore tend to cause attrition losses in advance of packaging. Thereafter these packaged products are subject to further attrition losses as a result of vibration in transportation to the point of consumption.

Resistance to bead break-down by attrition is of considerable economic importance because attrition produces a change in the bulk density of the product, a property of substantial concern in packaging. The bulk density determines the weight of material charged to the package by a packaging machine of the constant volume type, or the volume charged by a machine of the constant weight type. Hence, uncontrolled changes in bulk density lead to over or under fill of the packages, either of which conditions results in economic loss to the manufacturer because of such factors as package rejection by quality control, customer dissatisfaction, excessive weight fill, overflow of packages on packaging machine, etc.

It is customary to control the bulk-density of the product by adjusting one or more of the several variables associated with the operation of the spray-dried or film drier. However, if the dried product possesses poor mechanical strength, varying and unpredictable amounts of attrition occur between the dryer and the point of packaging. It has now been found that by adding stable, film forming polymeric materials to the detergent composition to be spray dried, the mechanical strength of the spraydried beads can be strengthened sufficiently to avoid the attrition necessarily attendant upon the various handling processes subsequent to the drying operations.

In reference to chlorinated solid bleach compositions contemplated by the invention, we may typically, though preferably, select the chlorinated component from the heterocyclic N-chloro imides, which are cyclic imides having from 4 to about 6 members in a ring having the following structure:

EXAMlNtK cyanuric acid (i.e. mono-, di-, and trichlorocyanuric acid) and hydantoin as well as N-chloro succinimide, N-chloro malonimide, N-chloro phthalimide and N-chloro naphthalimide. Most effective are those imides containing a plurality of chlorine-carrying nitrogen atoms, e.g. trichlorocyanuric acid, dichlorocyanuric acid, alkali metal salts of dichlorocyanuric acid, and the N-chloro hydantoins. Suitable N-chloro hydantoins include 1,3-dichloro 5,5 dimethyl hydantoin, N-monochloro-C, C-dimethylhydantoin, methylene-bis-(N-chloro-C, C-dimethylhydantoin); 1,3-dichloro-5-methyl-5-isobutylhydantoin; 1,3-dichloro-S-methyl-S-ethylhydantoin; 1,3-dichloro-5,5- diisobutylhydantoin; 1,3'dichloro-5-methyl 5 n-amylhydantoin, and the like. Among all such compounds, we prefer the alkali metal salts of dichlorocyanuric acid.

As previously indicated, the spray dried base for most products will contain a suitable organic detergent, the content of which may range from as low as about 1% to as high as about 20% in formulations where the spray dried material constitutes the complete product. With respect to solid bleach compositions, the spray dried base normally will contain between about 1 to 5% of surfactant, the beads being uniformly admixed with a selected chlorinated material which may constitute between about 20 to 25 weight percent of the mixture. Using the preferred sodium or potassium salts of dichlorocyanuric acid as the chlorinated material, the latter desirably will constitute between about 5-9% of the total mixture of the chlorinated salt and spray dried base in household bleaches, and between about 15-20% in industrial bleaches.

Suitable anionic detersive compounds are the soaps and the sulfated and sulfonated synthetic detergents, especially those anionic detergents having about 8 to about 26 and preferably about 12 to about 22 carbon atoms to the molecule. The sulfated and sulfonated compounds are well known in the art and may be prepared from suitable organic materials capable of sulfonation or sulfation. Preferred or the aliphatic sulfates and sulfonates of about 8 to 22 carbon atoms, an

hem aromatic sulfonatgg, The latter may be mnonuclear or ynuc ear to structure. More particularly, e aromatic nucleus may be derived from benzene, toluene, xylene, phenol, cresols, phenol ethers, naphthalgne, derivatives of phenanthrene nuclei, etc. e alkyl group may vary similarly. Thus, the alkyl group may be straight or branch chained and may consist of such radicals as dodecyl, pentadecyl, octyl, nonyl, decyl, keryl, mixed alkyls derived from fatty materials, cracked parafiin wax olefins, and polymers of lower mono olefins, etc.

Examples of suitable alkyl aromatic sulfonate detergents are the propylated naphtholene sulfonates, the mix naphthalene sulfonates, tetrahydronaphthale'ne sulfonates, Ir va'TrIIS'i utylated diphenyl sulfonates and phenyl-phenol sulfonates. Preferred are the higher alkyl aromatic sulfonates the sulfonated and alkylated benzene type compounds wherein the alkyl group is at least 8 and preferably about to about 16 carbon atoms.

Other suitable surfactants are the surface-active sulfated or sulfonated aliphatic compounds, preferably having 8-22 carbon atoms, such as the sulfuric acid esters of polyhydric alcohols incompletely esterified with higher fatty acids, e.g. coconut oil monoglyceride monosulfate, tallow diglyceride monosulfate; the long chain pure or mixed alkyl sulfates, e.g. lauryl sulfate, cetyl sulfate; the hydroxy sulfonated higher fatty acid esters, e.g. higher fatty acid esters of low molecular weight alkylol sulfonic acids, e.g. fatty acid esters of isethionic acid; the fatty acid ethanolamide sulfates; the fatty acid amides of amino alkyl sulfonic acids, e.g. lauric amide of taurine, and the like.

The cationic detergents include the long chain alkyl quaternary ammonium compounds, e.g. cetyl quaternary ammonium salts, which include those salts wherein the nitrogen atom may be part of an open chain or heterocyclic structure such as cetyl tri methyl ammonium chloride and cetyl pyridinium chloride. Other cationic agents are the diethylene amino ethyl oleyl amides.

Non-ionic surfactants include the polyoxyethylene ethers of alkyl aromatic hydroxy materials (e.g. the alkylated polyoxyethylene phenols) the polyoxyethylene ethers of long chain aliphatic alcohols, and the polyoxyethylene ethers of hydrophobic propylene oxide polymers.

Particularly effective for incorporation in high builder salt compositions to produce dried particles of increased mechanical strength are copolymers having in the particles the following formula:

The exact position of this ethylene linkage is indeterminate by presently known methods. The principal significance of molecular weight is that the polymeric group be sufficiently great in number that the material is capable of drying from solution or dispersion in the salt solution, in thin film form.

Commercially this copolymer in the anhydride form has been available as early as September 1961, as solid water soluble ethylene maleie anhydride resin sold by Monsanto Chemical Co., under the name, EMH Resin DX840-81. This product is described by Monsanto as having a viscosity of 80,000 centipoises (measured at 25 C. in a 1% solution at pH 9 using a Brookfield viscometer, No. 6 spindle at 5 rpm). This is representative of a molecular weight in excess of 10,000.

While the possibility of incorporating the resinous additive in a relatively broad range of about 0.1% and 5% of the bead composition is contemplated, in practice and because of the efficacy of this resin, it has been found that around 0.4% of the resin will satisfactorily reinforce the beads.

When this resin was added in the amount specified below in Table I, to a standard aqueous slurry of 60% solids content (solids composition by weight: 4.25% sodium dodecyl-benzenesulfonate, 16.5% tetrasodium pyrophosphate, polymeric resin (X), and salt cake q.s. to and a film was prepared and dried in a standard reproducible manner, the following relative strength values were obtained for films containing and lacking the resin.

TABLE I.-RELATIVE FILM. STRENGTHS Resin Added Percent Added Relative Film Strength None 0.0 1.00

EMA Resin DX840-81 0. 4 2.28

6 pie II, which represent products usable as household toward bead strength, these are required in such large detergents: percentages as to either unbalance the desired perform- EXAMPLE I ance of the product or be uneconomical.

We claim:

Formulas with the following composition have been 5 1. A spray drier substantially water soluble product in mlxed and spray dned m plant produclon' hollow bead form consisting essentially of a uniform mix- Formula A, l-'orn'.-uia I ture of at least 75% by weight of water soluble inorganic Percent Term" builder salt of the group consisting of alkali metal phos- Sodium dodccyl benione Sultanate 4.25 4.00 phates, alkali metal sulfates, alkali metal silicates and al- 3233232 531,jggfigit glg 1O kali metal carbonates, and between about 0.1% and 5% Eli-sheath fl-fil) 0. t l of normally solid ethylene maleic anhydride resin which 8 2E3 2; 3%; is film forming from solutions and dispersions containing said salt, said resin having the formula:

H B As can be noted, the only differences between For- 15 H g mulas A and B are the slight changes in the sodium alkyl A-(CC-CB aryl sulfonate and sodium sulfate levels and the addizion LH H H of 0.4% ethylene malcic anhydride copolymer in Forwherein A is hydrogen, i5 an integer representing mula B. However, the dried product of Formula B conmolecular Weight Over 10,000 and B is the Same as lhfi sistently had much greater bead stability than the dried 20 unit Within 1118 brackets CXCBPI that it has all ethylene product of Formula A. In a specific instance, the bull; linkage in place of o o the hydrogen atoms, said roddensity of the product out of the bottom of the spray uct being characterized by substantially increased attrition drier was able to be raised from 240 to 300 grams/liter resistance r u i g from the presence of Said resin. in order to meet a packaging specification of 326 grams/ A Product according 10 Claim in Which 6 p liter. Additionally, the product of Formula B has more Contains about 1 to 20% of a Water Soluble cationic uniformity in particle size and is improved in the resultionic 0r HOIIiOniC detergent ing appearance 3. A product according to cla1m 1, 1n WhlCh the con- EXAMPLE II tent of said resin is about 0.4% of the product.

g 4. A dry bleach composition comprising the product of Detergents WM] the folowmg Composmo were claim 1, containing uniformly admixed therein a solid mixed and spray (med m Plant production organic chlorinated water soluble bleach material con- Fmmma C Formula D stituting between about 2 to 25% of the total composition.

l'ercent Percent 5. The composition of claim 4, in which the spray dried Sodium dodccv; when, sumnm mm mm product contains an organic anionic surfactant in an 'Tt-trasodium Pyrophosphetc 5.00 5.00 amount sufiicient to give the product detersive properties ji f 0.4 in aqueous solution.

.525 6. The composition of claim 4, in which said chlorinat- D} es. Perfume and preservi- ..;1 Sodium sulfate 79-475 79075 ed material is of the group consisting of trichlorocyanuric 100.000 100.000 acid, dichlorocyanuric acid and alkali metal salts of di- 40 chlorocyanuric acid.

The only dlfference belween the F Formulas C and 7. The composition of claim 5, in which said chlorinated D is th c s s decrease In the Sqdwm sulfate level and material is of the group consisting of trichlorocyanuric the addition f the ethylene male: anhydnde copolymer acid, dichlorocyanuric acid and alkali metal salts of dito Formula D. The dried product of these formulas was chlorocyanuric acid packaged in what is essentially a constant volume packag- 8. The composition of claim 4 in which said product t; machine- The average P Overwmght 1:er Package contains between about 1% and 5% of an organic anionic would then e a measure of bead breakdown. as both surfactant and said chlorinated material is an alkali metal formulas were run at the same bulk density out of the salt of dichlomcyanuric acid sprgy i r, The overweight figu e for two Pmdutition 9. A spray dried product according to claim 1 wherein Perlods are below: said water-soluble solids comprise a surfactant selected from the group consisting of sulfated and sulfonated an- Periodl Period 11 I d T P d P 1on1c synthetic detergents, cationic long chain alkyl quaag ifgg fi f gg l ifg ternary ammonium compounds and fatty acid amides and p noniomc polyoxyethylene ethers. $333222: 3}; 3 3% i gi 10. A dry bleach composition according to claim 9 in- 11 ounces- 10, 000 5.92 6,800 1. s2 eluding 15% of said surfactant, the balance of said composition being essentiall alkali metal salt of chlorinated Formula C was packaged during period I. Formula D cyanuric acid y was packaged during period 11. It is evident that the ethyl- Refrences Cited ene maleic anhydride copolymer strengthened the bead 6O considerably in Formula D. UNITED ES PATENTS 2,870,093 1/1959 Ruff 252--135 EXAMPLE m 2,992,186 7/1961 Hellsten 252 135 Formula B of Example I may be uniformly admixed 3,060,124 10/ 1962 Gina 252-435 wi h p t si m i hl r cyanurate to give the latter 6% 3,073,806 1/1963 Reinhard weight concentration in the mixture which is useable as 3,093,590 6/19 3 Ferris 252 89 household dry bleach.

It may be observed that the invention is distinctively FOREIGN PATENTS characterized by the low amounts of polymer needed to 583,761 9/1951 a adaachieve the desired bead strength and attrition resistance. 7 Whereas to varying degrees, other additives such as sugar, LEON ROSDOL certain gums and surface active agents may contribute MAYER WEINBLATT Examiner 

